[Bug ipa/92394] operand_equal_p should compare as base+offset when comparing addresses

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92394

--- Comment #1 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
Following testcase is mergeable:

struct a {int a; int b;};
struct b {int c; short d;};

void *
retadr1(struct a *a)
{
  return &a->b;
}
void *
retadr2(struct b *a)
{
  return &a->d;
}